document.write( "Question 768947: Last year, Melissa had to $30000 invest. She invested some of it in an account that paid 6% simple interest per year, and she invested the rest in an account that paid 9% simple interest per year. After one year, she received a total of $1980 in interest. How much did she invest in each account? \n" ); document.write( "
Algebra.Com's Answer #468635 by mananth(16946)\"\" \"About 
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Part I 6.00% per annum ------------- Amount invested =x
\n" ); document.write( "Part II 9.00% per annum ------------ Amount invested = y
\n" ); document.write( " 30000
\n" ); document.write( "Interest----- 1980.00
\n" ); document.write( "
\n" ); document.write( "Part I 6.00% per annum ---x
\n" ); document.write( "Part II 9.00% per annum ---y
\n" ); document.write( "Total investment
\n" ); document.write( "x + 1 y= 30000 -------------1
\n" ); document.write( "Interest on both investments
\n" ); document.write( "6.00% x + 9.00% y= 1980
\n" ); document.write( "Multiply by 100
\n" ); document.write( "6 x + 9 y= 198000.00 --------2
\n" ); document.write( "Multiply (1) by -6
\n" ); document.write( "we get
\n" ); document.write( "-6 x -6 y= -180000.00
\n" ); document.write( "Add this to (2)
\n" ); document.write( "0 x 3 y= 18000
\n" ); document.write( "divide by 3
\n" ); document.write( " y = 6000
\n" ); document.write( "Part I 6.00% $ 24000
\n" ); document.write( "Part II 9.00% $ 6000
\n" ); document.write( "
\n" ); document.write( "CHECK
\n" ); document.write( "24000 --------- 6.00% ------- 1440.00
\n" ); document.write( "6000 ------------- 9.00% ------- 540.00
\n" ); document.write( "Total -------------------- 1980.00
\n" ); document.write( "
\n" ); document.write( "m.ananth@hotmail.ca
\n" ); document.write( " \n" ); document.write( "
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